Cell Plug-in Hybrid Electric Vehicle Research Articles

Vehicle choice modeling for emerging zero-emission light-duty vehicle markets in California

To predict the market dynamics of various zero-emission vehicle (ZEV) technologies, this study introduces a dynamic discrete vehicle choice model (VCM) that investigates the probabilities associated with 14 decision factors, applying these to the purchase of ZEVs from 2020 to 2040. Market share and penetration results are presented under eight scenarios, that vary by vehicle costs infrastructure development and incentive strategies. The findings suggest that in the early years, incentives alone may not generate significant market penetration of ZEVs before the infrastructure meets the basic convenience for daily use, especially for fuel cell vehicles (FCVs). However, in later years, incentives play a more important role in the market penetration of ZEVs under well-defined infrastructure networks. By 2040, battery electric vehicles (BEVs) are projected to dominate the market in California. Plug-in hybrid electric vehicles (PHEVs) and FCVs may experience a decline in market share due to improved charging convenience, which benefits the market penetration of BEVs. However, fuel cell plug-in hybrid electric vehicles (FC-PHEVs) could still be beneficial if accessible models are available, considering the limited availability of hydrogen refueling stations. The goal set by the California Air Resources Board (CARB) is achievable, but it requires a sustained combination of measures; no single effort can achieve it. These measures include technological improvements to reduce the cost of ZEVs, a wider range of models available for consumers to choose from based on their desired performance, the establishment of infrastructure (battery chargers and hydrogen dispensers), and attractive incentives aimed at promoting ZEV adoption. The proposed methodology can be adapted for other regions in the United States and globally by carefully examining the inputs for each decision factor at the desired scale.

Predictive energy management of fuel cell plug-in hybrid electric vehicles: A co-state boundaries-oriented PMP optimization approach

This paper proposes a predictive energy management strategy of FC PHEV based on PMP and co-state boundaries. The model predictive control (MPC) problem is established and transformed as a two-point-boundary-value one by PMP theory, and the physical constraints of FC power, FC power varying rate, and battery current, are merged by methodical derivatives. To gain the accurate co-state boundaries, the Karush-Kuhn-Tucker condition, for the first time, is employed to derive the general expressions, and a correction method is developed to modify the co-state boundaries for effectiveness guarantees. By inputting the feedback SOC, power demand, and the unified constraint, the shrunken enclosed range between the developed co-state boundaries can be determined in real time, thereby benefiting the efficient co-state calibration. Based on the co-state bounds, the concise but highly effective heuristic rules are proposed to calibrate the co-state online iteratively, and an analytical method is proposed to fast find the optimal solution of Hamilton function. The global optimality of the proposed strategy for the addressed MPC problem is also strictly proved. The validations and sensitivity analysis for the initial state of charge (SOC), the SOC reference, the predictive velocity accuracy, and the horizon length, are implemented under simulations, and the hardware-in-the-loop (HIL) experiments are carried out to verify the effectiveness of the proposed strategy under on-board environment. The results yield that, the proposed strategy can implement the timely and high-efficiency co-state updates, the smooth control commands, the expected SOC tracking effects, and improve the fuel economy. Additionally, <0.5 ms per sample is spent for the predictive horizon length 40 under HIL tests, indicating the real-time applicability of proposed strategy.

Hydrogen Integration for Achieving Net-Zero Emissions with Plug-in Fuel Cell Hybrid Electric Vehicles

Currently, to achieve net-zero emissions, the transport sector is going through a decarbonization process, with Battery Electric Vehicles (BEVs) leading the race. However, these vehicles present a limited range and high charging time as barriers to replacing 100% of the transport sector. Also, BEVs cannot achieve net-zero emissions given that the electric rechargeable stations are powered by the local grid electricity. Thus, even though electric vehicles do not produce greenhouse gas (GHG) emissions directly; there are indirect emissions linked to the electricity used, relying on the balance between renewable and non-renewable energy sources in the local network. In this study, green Hydrogen is assessed as a possible solution to reach net-zero emissions with Fuel Cell Plug-in Hybrid Electric Vehicles (FC-PHEVs) that count with a greater range. A specific model of a cradle-to-grave life cycle is developed, allowing the assessment of its environmental impacts. Consequently, 3 scenarios are implemented to be assessed and compared using the model. The analysis shows that a considerable part of GHG emissions of Hydrogen implementation is found in its transportation, although research is being carried out on alternative solutions to mitigate this drawback.

Fuel cell plug-in hybrid electric vehicle thermal management strategy in parking time for low-temperature environments

This work presents a thermal management strategy for fuel cell hybrid electric vehicles under low-temperature conditions. Protecting the fuel cell system (FCS) and battery pack from such operating conditions prevent their degradation and performance decay. Thus, an approach similar to the keep-warm strategy is proposed to avoid the well-known issues related to the thaw-at-start methods, as well as promote a rapid startup after long parking periods. Particularly, the present work proposes a strategic synergy between the battery pack recharging and thermal management during the parking phase, so as to minimize the fuel consumption, while featuring vehicle to grid functionality and rapid startup of the vehicle when resuming driving. Such thermal management strategy was evaluated via simulation analyses, considering the transient thermal dynamics of the FCS and battery pack under low-temperature conditions and the temperature control strategy. The results outlined how proper exploitation of plugin functionalities, beyond introducing innovative vehicle-to-grid (V2G) concepts to suitably link driving to parking phases energy management, also allows for low-temperature safe thermal management of involved electrochemical devices. Finally, an economic analysis demonstrated that the proposed plugin-based vehicle to grid scenario presents a cost-saving potential of up to 56 % with respect to non V2G charge-sustaining one.

Identification of the Optimal Passenger Car Vehicle Fleet Transition for Mitigating the Cumulative Life-Cycle Greenhouse Gas Emissions until 2050

We present an optimization model for the passenger car vehicle fleet transition—the time-dependent fleet composition—in Germany until 2050. The goal was to minimize the cumulative greenhouse gas (GHG) emissions of the vehicle fleet taking into account life-cycle assessment (LCA) data. LCAs provide information on the global warming potential (GWP) of different powertrain concepts. Meta-analyses of batteries, of different fuel types, and of the German energy sector are conducted to support the model. Furthermore, a sensitivity-analysis is performed on four key influence parameters: the battery production emissions trend, the German energy sector trend, the hydrogen production path trend, and the mobility sector trend. Overall, we draw the conclusion that—in any scenario—future vehicles should have a plug-in option, allowing their usage as fully or partly electrical vehicles. For short distance trips, battery electric vehicles (BEVs) with a small battery size are the most reasonable choice throughout the transition. Plug-in hybrid electric vehicles (PHEVs) powered by compressed natural gas (CNG) emerge as promising long-range capable solution. Starting in 2040, long-range capable BEVs and fuel cell plug-in hybrid electric vehicles (FCPHEVs) have similar life-cycle emissions as PHEV-CNG.

Enhancing fuel cell durability for fuel cell plug-in hybrid electric vehicles through strategic power management

Fuel cell plug-in hybrid electric vehicles (FC-PHEVs) can have extended range while utilizing cheap grid electricity, but has poor durability of onboard fuel cells due to dynamic loading. In this study, fuel cell durability is enhanced significantly for a novel configuration of FC-PHEVs with three fuel cell stacks through strategic power management by making each fuel cell stack work only at a fixed operating point (i.e., constant output power) and by shortening its active time (operation) via on-off switching control. A hysteresis control strategy of power management is designed to make the active time evenly distributed over the three fuel cell stacks and to reduce the number of on-off switching. The results indicate that the durability of the onboard fuel cells can be increased 11.8, 4.8 and 6.9 times, respectively, for an urban, highway and a combined urban-highway driving cycle. This enhanced fuel cell durability is derived from the fact that the average power demand of real-time driving cycles is only a fraction of the maximum power that FC-PHEVs could provide, and substantially increased durability can be used to reduce the over-design, hence the cost, of fuel cells.

Hydrogen vehicles: Impacts of DOE technical targets on market acceptance and societal benefits

Hydrogen vehicles (H2V), including H2 internal combustion engine, fuel cell and fuel cell plug-in hybrid, could greatly reduce petroleum consumption and greenhouse gas (GHG) emissions in the transportation sector. The U.S. Department of Energy has adopted targets for vehicle component technologies to address key technical barriers to widespread commercialization of H2Vs. This study estimates the market acceptance of H2Vs and the resulting societal benefits and subsidy in 41 scenarios that reflect a wide range of progress in meeting these technical targets. Important results include: (1) H2Vs could reach 20–70% market shares by 2050, depending on progress in achieving the technical targets. With a basic hydrogen infrastructure (∼5% hydrogen availability), the H2V market share is estimated to be 2–8%. Fuel cell and hydrogen costs are the most important factors affecting the long-term market shares of H2Vs. (2) Meeting all technical targets on time could result in about an 80% cut in petroleum use and a 62% (or 72% with aggressive electricity de-carbonization) reduction in GHG in 2050. (3) The required hydrogen infrastructure subsidy is estimated to range from $22 to $47 billion and the vehicle subsidy from $4 to $17 billion. (4) Long-term H2V market shares, societal benefits and hydrogen subsidies appear to be highly robust against delay in one target, if all other targets are met on time. R&D diversification could provide insurance for greater societal benefits. (5) Both H2Vs and plug-in electric vehicles could exceed 50% market shares by 2050, if all targets are met on time. The overlapping technology, the fuel cell plug-in hybrid electric vehicle, appears attractive both in the short and long runs, but for different reasons.

Fuel cell Plug-in Hybrid Electric Vehicle anticipatory and real-time blended-mode energy management for battery life preservation

In this paper, the energy management problem for a Fuel Cell Plug-in Hybrid Electric Vehicle is investigated using a real-time power splitting method that preserves the battery pack life. The reduction of high-power demand during the vehicle stop-and-go operations and the limitation of the batteries' minimum energy to a prescribed level are the two aspects considered in this study. Using a longitudinal motion model of an experimental small utility truck, a multi-criteria optimization problem, including the hydrogen/electricity cost ratio and the anticipation of the high-power demand, is formulated and solved. The analysis of the effects of the fuel cell and the battery efficiency degradations demonstrated that there exists a minimum cost ratio that prevents the Energy Management System to adequately limit the batteries' depletion with the contribution of the Fuel Cell power. The overall control system does not require a prior knowledge of the trip information. Therefore, the real-time implementation of this system is realistic. Compared with a rule-based Energy Management System, the proposed optimal and real-time approach provides up to 5% of hydrogen saving whilst maintaining the Battery Pack energy close to the minimum prescribed energy. The high-power demand reduction and the depletion limitation enable the Energy Management System to preserve the batteries' life.

Proton exchange membrane fuel cells cold startup global strategy for fuel cell plug-in hybrid electric vehicle

This paper investigates the Proton Exchange Membrane Fuel Cell (PEMFC) Cold Startup problem within the specific context of the Plugin Hybrid Electric Vehicles (PHEV). A global strategy which aims at providing an efficient method to minimize the energy consumption during the startup of a PEMFC is proposed. The overall control system is based on a supervisory architecture in which the Energy Management System (EMS) plays the role of the power flow supervisor. The EMS estimates in advance, the time to start the fuel cell (FC) based upon the battery energy usage during the trip. Given this estimation and the amount of additional energy required, the fuel cell temperature management strategy computes the most appropriate time to start heating the stack in order to reduce heat loss through the natural convection. As the cell temperature rises, the PEMFC is started and the reaction heat is used as a self-heating power source to further increase the stack temperature. A time optimal self-heating approach based on the Pontryagin minimum principle is proposed and tested. The experimental results have shown that the proposed approach is efficient and can be implemented in real-time on FC-PHEVs.

Two-Stage Energy Management Control of Fuel Cell Plug-In Hybrid Electric Vehicles Considering Fuel Cell Longevity

As the dependence on fossil fuel increases in the transportation sector, more attention has been paid to the energy management control of proton exchange membrane fuel cell (PEMFC) plug-in hybrid electric vehicles (PHEVs). In this paper, the energy management control problem for a series plug-in PEMFC/Li-ion battery hybrid midsize sedan is formulated and investigated using a two-stage controller (TSC). The control objective is to minimize hydrogen consumption and simultaneously protect PEMFC health. The proposed TSC consists of two controllers designed in two stages with different control functions. During the first design stage, a predictive controller is developed using the telemetry equivalent consumption minimization strategy (T-ECMS) approach to predict the global battery state-of-charge (SOC) optimality trend and local control reference, without regard for the PEMFC health constraints. During the second stage of design, a tracking controller is designed to track the local control reference with respect to the PEMFC health constraints and other physical limitations at the current control step, which ensures that the system follows the optimal battery SOC reference over a long time horizon. Finally, the effectiveness of the proposed TSC is compared with the T-ECMS and an electric vehicle controller (EVC) under the Matlab/Simulink software environment. The results demonstrate that the TSC achieves a reasonable tradeoff between hydrogen fuel consumption and PEMFC health protection.

Implementation of a fuel cell plug-in hybrid electric vehicle and factors affecting transportation policy

With today's rapidly changing vehicle market, many advanced vehicle technologies are being evaluated at varying levels of governments and private organizations. This paper is intended to provide insight into the evaluation of vehicle power train technology and a brief state of the industry regarding new vehicle technology and alternative fuels. The paper proposes that public policymakers focus on metrics such as well-to-wheel greenhouse gas emissions and criteria air pollutants. Such a focus makes hydrogen vehicle technology much more attractive. The integration of a plug-in hydrogen fuel cell vehicle is described as it is found to be a promising vehicle architecture for the long-term automotive power train. Detailed mechanical and electrical integration is described in the paper. An innovative control system that was used on this vehicle and the control system is described. Copyright © 2011 John Wiley & Sons, Ltd.

Design layout of hydrogen research and development garage

Research and development programs toward fuel cells and other hydrogen technologies have increased significantly during the past two decades. These programs require appropriate facilities to undertake the research and development programs. This paper discusses the design layout of one such facility, the “Missouri S&T EcoCAR Hydrogen Vehicle Garage”, which can be used as a model while designing a hydrogen R&D garage. The Missouri S&T EcoCAR garage is a 12.2 m × 7.6 m garage situated at the Missouri University of Science and Technology (Missouri S&T) and serves as the headquarters for the Missouri S&T EcoCAR team. Within the garage, students will gain real-world, hands-on experience by transforming a standard production vehicle into a hydrogen Fuel Cell Plug-in Hybrid Electric Vehicle (FC-PHEV). The garage is classified as a Class 1 Division 2, Group B hazardous location and is equipped to safely test and integrate the vehicle prototype. Specifically, the design includes (i) a hydrogen gas detection system, (ii) hazardous location electrical service, heating, ventilation and air-conditioning, lighting, and compressed air systems, and (iii) emergency backup electric power system with alarms/monitors/security cameras for the hydrogen R&D facility. The garage will be connected to an external backup power supply unit which will be powered by a PEM fuel cell.

Techno-economic and behavioural analysis of battery electric, hydrogen fuel cell and hybrid vehicles in a future sustainable road transport system in the UK

This paper conducts a techno-economic study on hydrogen Fuel Cell Electric Vehicles (FCV), Battery Electric Vehicles (BEV) and hydrogen Fuel Cell plug-in Hybrid Electric Vehicles (FCHEV) in the UK using cost predictions for 2030. The study includes an analysis of data on distance currently travelled by private car users daily in the UK. Results show that there may be diminishing economic returns for Plug-in Hybrid Electric Vehicles (PHEV) with battery sizes above 20 kWh, and the optimum size for a PHEV battery is between 5 and 15 kWh. Differences in behaviour as a function of vehicle size are demonstrated, which decreases the percentage of miles that can be economically driven using electricity for a larger vehicle. Decreasing carbon dioxide emissions from electricity generation by 80% favours larger optimum battery sizes as long as carbon is priced, and will reduce emissions considerably. However, the model does not take into account reductions in carbon dioxide emissions from hydrogen generation, assuming hydrogen will still be produced from steam reforming methane in 2030.

Air quality and environmental impacts of alternative vehicle technologies in Ontario, Canada

This study is focused on the province-wide emissions in Ontario, Canada and urban air pollution in the city of Toronto. The life-cycle (LC) impacts of utilizing alternative fuels for transportation purposes is considered in terms of six major stressors for climate change, acidification and urban air quality. The vehicles considered are plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs) and fuel cell plug-in hybrid electric vehicles (FCPHEVs). Modeling of the penetration rates for these types of vehicles has been completed based on the maximum base-load capacity of Ontario's electricity grid to accommodate the generation of hydrogen and charging of vehicles using grid electricity. Results show that the reduction in greenhouse gas emissions from adoption of PHEVs or FCVs will exceed 3% of the current emissions from the transportation sector in Ontario while FCPHEVs may achieve almost twice this reduction. All vehicles exhibit similar impacts on the precursors for photochemical smog although the province-wide effects differ significantly.